 #define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
const int N = 1010;
int f[N][N];
int n, m;
char a[N], b[N];
int main()
{
    cin >> n;
    cin >> a + 1;
    cin >> m;
    cin >> b + 1;
    for (int i = 0; i <= n; i++) f[i][0] = i;
    for (int i = 0; i <= m; i++) f[0][i] = i;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            f[i][j] = min(f[i - 1][j] + 1, f[i][j - 1] + 1);
            if (a[i] == b[j]) f[i][j] = min(f[i][j], f[i - 1][j - 1]);
            else f[i][j] = min(f[i][j], f[i - 1][j - 1] + 1);
        }
    }
    cout << f[n][m];
    return 0;
}